| 摘要 |
PURPOSE:To allow the rapid formation of the MIDI chords exactly corresponded to original performance by comparing detected envelope data and previously stored fundamental tone envelope data by a crosscorrelation and deciding the fundamental tones generated by a musical instrument. CONSTITUTION:The performance tones of the musical instrument 1 which generates the plural fundamental tones of discrete frequencies and the harmonic overtones thereof according to performance operations are converted to audio signals by a microphone 2 and thereafter, these signals are converted to digital waveform data by a A/D converter 4. Of this output waveform data, the envelope data of the waveform data of each of the respective fundamental tones extracted by a band-pass filter group 5 are detected respectively by a CPU 7. The extracted envelope data and the fundamental tone envelope data A1 previously stored in a RAM 9 are compared by the crosscorrelation and the fundamental tones generated by the musical instrument 1 are decided and, therefore, the fundamental tones are surely and instantaneously decided. The MIDI chords exactly corresponded to the original performance are rapidly formed in this way. |
